A gaseous reaction mixture at 300 K is represented by a Maxwell–Boltzmann curve with an activation-energy line at Ea. Two separate modifications are considered.
• Modification 1: Increase the temperature to 330 K. Students sketch a new distribution (curve A) whose peak is lower and shifted to higher kinetic energy; the activation-energy line remains at Ea.
• Modification 2: Add a catalyst that lowers the activation energy to 0.75Ea without changing the molecular-energy distribution (curve B overlays the original curve, but a new activation-energy line is drawn at 0.75Ea).
Based on the areas under the relevant curves that lie to the right of their respective activation-energy lines, which ranking orders the reaction rates from slowest to fastest?
a) A<Original<B
b) Original<B<A
c) Original<A<B
d) B<Original<A